1. Field of the Invention
The present invention relates to a moving object which is driven by an electric motor and includes a secondary battery chargeable by wireless communication. The present invention also relates to a wireless power feeding system including a moving object and a power feeding device which supplies power to the moving object through wireless communication. The present invention further relates to a wireless communication method for use in the wireless power feeding system.
2. Description of the Related Art
In recent years, energy saving, creation and storage technologies are attracting more attention because environmental problems such as global warming are becoming more severe. In the case of a moving object with a secondary battery, i.e., a moving object which is driven by an electric motor using power provided from a secondary battery regardless of whether they have two wheels or four wheels, such as an electric car and a bicycle having a motor, energy storage techniques are used and in addition, an amount of carbon dioxide emissions can be reduced. Therefore, techniques used for such a moving object are particularly being developed actively.
At present, the secondary battery of the moving object can be charged by using a general home AC power source as a power feeding device or by using a public power feeding facility having a power feeding device such as a high-speed battery charger. In either case, a connector which makes electric connection by insertion of a plug into a socket is commonly used.
For charging of a secondary battery using such a connector, an electric connection between a moving object and a power feeding device is made by bringing a conductor of a plug into contact with a conductor of a socket. This requires cumbersome plugging-in/out operations for every charging, which may deteriorate the connector due to repeated charging operations. In addition, a large-sized moving object such as an electric car requires high power for charging. This may raise safety issues since damage from an electric shock or electric leakage due to moisture or the like may be significant. Accordingly, special care is needed for handling the connector.
In order to avoid the above problems associated with a connector, research and development are being conducted to propose a wireless power feeding system for supplying power from a power feeding device to a moving object by wireless communication (for example, see Patent Document 1). Use of such a wireless power feeding system allows a secondary battery to be charged without using any connector.